Origin of Japanese Endemic Species Iris setosa var. nasuensis and I. setosa var. hondoensis

抄録

In this study, we clarified the origin of Iris setosa var. nasuensis (2n=54) and I. setosa var. hondoensis (2n=53), which are endemic to Japan. Four interspecific hybrids were obtained from the cross I. setosa var. setosa (2n=2x=38) × I. laevigata (2n=2x=32). Two of these, DSL1 and DSL2, survived, and were shown to be allotriploid hybrids (2n=54) between I. setosa var. setosa (n=38) and I. laevigata (n=16) by mitotic and meiotic observations and random amplified polymorphic DNA (RAPD) analyses. In addition, it was shown that I. setosa var. nasuensis and I. setosa var. hondoensis were derived from allotriploid hybrids (2n=54) of I. setosa var. setosa and I. laevigata and their aneuploids (2n=53) from meiotic observations and RAPD analyses of I. setosa var. nasuensis, I. setosa var. hondoensis, DSL1, DSL2, I. setosa var. setosa (2x), and I. laevigata. These conclusions were supported by the characterization of these species (lines) and SL4 (2n=53) obtained from the cross I. setosa var. setosa (4x) × I. laevigata. Finally, the mechanisms of 2n (n=38) and 2n−1 (n=37) gamete production of I. setosa var. setosa (2x) are discussed.